Dana-Farber Cancer Institute researchers have developed a systematic platform for discovering molecular glue degraders, a class of drug-like compounds that can redirect the cell’s own protein-disposal machinery toward disease-associated proteins. The approach could substantially broaden the number of proteins that can be eliminated therapeutically, potentially opening new strategies for treating cancer and other diseases. The study, published in Nature, also describes the first molecular glue degrader known to be activated through a metabolic modification inside cells.
Protein degradation therapies work by exploiting the ubiquitin-proteasome system, the cell’s built-in recycling network. In this process, enzymes known as E3 ligases attach molecular tags called ubiquitin to selected proteins. Once tagged, the proteins are transported to the proteasome, a cellular structure that breaks them down. Molecular glue degraders do not simply block a protein’s activity. Instead, they bring an E3 ligase into contact with a previously unrelated cellular protein, effectively redirecting the ligase so that the target is marked for destruction.
The concept has already transformed thinking about proteins considered difficult or impossible to inhibit with conventional drugs. In 2014, Benjamin Ebert, MD, PhD, president and CEO of Dana-Farber, helped establish that lenalidomide, a multiple myeloma treatment, works by acting as a molecular glue degrader of a transcription factor. Transcription factors often lack the deep binding pockets required for traditional inhibitors, leading researchers to describe them as “undruggable.” Their destruction through induced protein-protein interactions demonstrated that drug discovery could target the presence of a protein rather than merely interfere with its function.
Despite the promise of the technology, currently developed protein degraders rely on only a small fraction of the approximately 600 E3 ligases encoded by the human genome. Dana-Farber’s new platform is designed to explore this largely untapped biological diversity. The system begins by attaching selected E3 ligases to magnetic beads in laboratory wells. Researchers then expose the immobilized enzymes to cellular lysate, which contains the broad mixture of proteins found inside cells, together with a library of chemical compounds.
A compound is considered a potential hit when it binds to an E3 ligase and increases the ligase’s affinity for another protein in the cellular mixture. This induced proximity can cause the recruited protein to accumulate around the drug-bound ligase, creating the molecular arrangement required for degradation. The researchers used mass spectrometry to identify the proteins associated with each ligase-compound combination. This allowed them to determine which cellular proteins might be recruited and tagged for destruction after the complex was introduced into living cells.
The team tested the discovery system against seven E3 ligases and identified an interaction between the protein DDX18 and DCAF11, an understudied member of the E3 ligase family. By progressively narrowing the chemical library, the researchers traced the activity to a compound known as M12. The result initially appeared to offer a straightforward example of a new molecular glue degrader. However, when the investigators attempted to use M12 in cells to eliminate DDX18, the compound failed to produce the expected degradation.
That unexpected failure led the researchers to examine the molecular complex in greater detail. Using cryo-electron microscopy, co-first author Franziska Wachter, MD, and colleagues determined that M12 had undergone a chemical alteration called glutathionylation. This process involves the attachment of glutathione, a small molecule involved in maintaining cellular redox balance, to another molecule or protein. The modification changed M12 into its active form, explaining why the original compound behaved differently in the test tube and in living cells.
The finding suggests that molecular glues may be regulated by the metabolic state of a cell rather than functioning as permanently active compounds. M12 became effective in cells with elevated levels of metabolites associated with oxidative stress, a condition frequently observed in cancer cells because of their altered metabolism, rapid proliferation and demanding growth environment. In principle, this type of activation could allow future degraders to operate preferentially in diseased cells while remaining less active in normal tissue, although extensive research will be required to determine whether such selectivity can be converted into a safe medicine.
Further experiments showed that activated M12 was not restricted to DDX18. By modifying the proteins recruited to the DCAF11 complex, the researchers were able to direct degradation toward several additional targets, including SMARCA2, WEE1 and CDK7, all of which have important roles in cancer biology. The results represent a proof of principle for a scalable discovery strategy rather than the identification of a finished drug candidate. Nevertheless, the work demonstrates how combining chemical screening, proteomics, structural biology and cell-based testing can reveal unexpected forms of degrader activity. Eric Fischer, PhD, and Ebert said the platform could accelerate the discovery of molecular glues that expand the range of cancer-related proteins accessible to therapeutic degradation.
Subject of Research: Systematic discovery of molecular glue degraders and metabolically activated protein degradation for cancer therapy.
News Publication Date: 6-Aug-2026
Web References: Dana-Farber Cancer Institute: https://www.dana-farber.org/ ; Eric Fischer, PhD: https://www.dana-farber.org/find-a-doctor/eric-fischer ; Benjamin Ebert, MD, PhD: https://www.dana-farber.org/find-a-doctor/benjamin-levine-ebert ; Franziska Wachter, MD: https://www.dana-farber.org/find-a-doctor/franziska-wachter
References: Nature, article publication date 5-Aug-2026.
Keywords: molecular glue degraders, targeted protein degradation, E3 ligases, DCAF11, DDX18, M12, glutathionylation, oxidative stress, cancer drug discovery, cryo-electron microscopy, proteomics, molecular biology
